Treatment of hydrocarbon oils



Oct. 29, 1935. c DUBBS 2,018,708

TREATMENT OF HYDROCARBON OILS Filed June 1, 1951 FURNACE l4 INVENTORCARBON P. DUBBS BY M0256 ATTO Patented Oct. 29, 1935 UNETED STATES2,018,708 TREATMENT or HYDROCARBON OILS Carbon P. Dubbs, Chicago, Ill.,assignor to Universal Oil Products Company, Chicago, 111., a corporationof South Dakota Application June 1, 1931, Serial No. 541,149

3 Claims.

This invention relates to the treatment of hydrocarbon oils, and moreparticularly refers to an improved process for the conversion of rela--tively high boiling hydrocarbons into more valu- 5 able products. Amongits aims and objects is the production of high yields of high anti-knockquality motor fuel.

In one of its specific embodiments the invention comprises subjectinghydrocarbon oils to heat treatment at elevated temperature andsuperatmospheric pressure, discharging the heated hydrocarbons at theirconversion temperature into a reaction zone wherein the non-vaporized Vresidue is maintained at what is commonly termed a low level to avoid along time element in the treatment of the said non-vaporizedhydrocarbons and to. avoid the production of suspended carbonaceous orpitchy material commonly referred to as B. S.; separately withdrawingthe non-vaporized residue and the vapors, the withdrawal of the latterbeing effected at a point remote from the point of introduction of theheated hydrocarbons into the reaction zone, separately discharging thevapors and non-vaporized residue into a zone of reduced pressure whereinthe vapors and non-vaporized residue are separated, the nonvaporizedresidue being sent to storage and the vapors passing to a fractionatingzone, returning the reflux condensate from the reaction zone to theheating element for reconversion, passing the fractionated vapors to acooler and condenser and collecting the condensed overhead product.

Among the important improvements of the in- -vention is the withdrawalof the vapors from the reaction zone at a point remote from the point ofintroduction while separately withdrawing the non-vaporized residue. Theremoval of the vapors in this manner permits a prolonged and uniformtreatment in the reaction zone, pre- Venting over-cracking ofhydrocarbon components on the one hand and under-cracking on the other.Likewise, the maintenance of a low level of liquid in the reaction zoneprevents over-cracking and undue formation of suspended carbonaceousmaterial therein. Other features and advantages of the invention willbecome more apparent by reference to the accompanying dia-' grammaticdrawing illustrating one form of apparatus suitable for carrying out theoperation of the invention.

Raw oil charging stock may be fed through line I, valve 2 and pumped bymeans of pump 3 through line 4., valve 5, into fractionator 6, whereinit undergoes heat exchange by direct contact with the vapors arisingtherein, cooling the vapors and assisting in control of theirfractionation, while at the same time heating the charging stock. Thereflux from the condenser 6 together with the raw oil passes throughline 1,- valve 8, 5

and is pumped by means of pump 9 through line Hi, controlled by valve IIand valve I2 into the heating element I3 located in furnace M, whereinit is raised to a suitable conversion temperature, or a portion or allof the raw oil may be fed 10 erably under superatmospheric pressureleaves 15 the heating element'l3 and passes through line l5, valve l5,intothe reaction chamber ll, wherein it undergoes conversion andseparates into vapors and non-vaporized residue. The non-vaporizedresidue may be withdrawn through line 20' I8, valve I 9 and introducedinto the vaporizer or flashing zone 20. The vapors are withdrawn at apoint remote from the point of introduction of the hydrocarbons into thereaction chamber through line 2|, valve 22 and may be intro- 25 ducedinto the vaporizing or reduced pressure zone 20.

It is one of the preferable features of the process, if not essential,to maintain a low liquid level in the reaction chamber ll so that themajor con- 30 version will occur in the vapor phase and the conversionof the non-vaporized liquid residue be reduced to the minimum consistentwith the prevention of the formation of suspended carbonaceous or pitchymaterial. 35

Non-vaporized liquid residue in reaction chamber 20 may be withdrawnthrough line 23, and valve 24. Vapors leaving the vaporizing or flashingzone 20 may be passed through line 25 and valve 26 into the fractionator6, wherein they 40 undergo heat exchange as heretofore described withthe oil introduced therein and the heavier portions of reflux condensatemay be returned together with the raw oil for reconversion. The

fractionated vapors leaving the fractionator 6 45 may pass through line21, valve 28, cooler and condenser 29 and through line 30, valve 3|,into receiver 32, wherein the fractionated overhead product of theprocess is collected. Liquids accumulating in receiver 32 may bewithdrawn 50 though line 33, valve 34 and pass to storage. Gases may bewithdrawn through line 35, controlled by valve 36, which may also servein part to control the pressure on the process.

The operating conditions may vary over a wide 55 range of temperaturesand pressures, temperatures ranging from 850 F. to 1200" F. andpressures ranging from atmospheric to high superatmospheric pressure,for example up to 2000 pounds per square inch may be employed. Thepreferred range of temperatures may vary from 900 F. to 975 F. andpreferred pressures may range from 100 pounds per square inch to 500pounds per square inch. Pressures upon the process will be equalizedwith respect to each other or differential pressures may be employed.Preferably the pressures on the heating element and reaction chamber arehigh with respect to those upon the vaporizing zone, fractionator,condenser and receiver.

The specific conditions employed will depend upon the charging stockbeing treated as well as upon the results desired.

As a specific example of the results obtainable by the operation of theprocess of my invention, a Pennsylvania fuel oil distillate ofapproximately 4=0-42 A. P. I. gravity may be treated and will produceapproximately 72% of gasoline having an anti-knock value equivalent toapproximately 60% benzol in admixture with Pennsylvania straight rungasoline and 75% iso-octane in admixture with normal heptane. Whenmaintaining a temperature of approximately 950 F. at the exit of theheating element IS the pressure upon the heating element and thereaction chamher is 300 pounds per square inch. Under these conditionpressures of approximately 50 pounds per square inch may be maintainedupon the Va porizing zone and the remaining portions of the system,namely, the fractionator, condenser and receiver. At the same timeapproximately 10% of non-vaporized residue which may be employed forfuel oil will be produced, the remainder of the products being gas and avery small amount of carbon.

When treating a Mid-Continent fuel oil, temperatures of approximately925 F. may be employed in the heating element and pressures of 250pounds per square inch upon the heating elemerit and reaction chamberare satisfactory. Re-

duced pressures upon the vaporizing zone, fractionating zone, condenserand receiver are employed. In the present operation 30 pounds per squareinch on the vaporizing zone will be satisfactory with differentialpressures between these elements as a result of the pressure droptherethrough.

Under these conditions approximately 58% of motor fuel having ananti-knock value equivalent to 50% benzol in admixture: withPennsylvania straight run gasoline may be produced, making at the sametime approximately 30% non-vaporized residue suitable for fuel oil, theremaining products being gas and a very small proportion of coke.

I claim as my invention:

1. A process of hydrocarbon oil' conversion 5 which comprises forcing astream of hydrocarbon oil through a heating zone where it is raised tocracking temperature, discharging said heated stream into an enlargedreaction zone, causing the products of reaction to traversesubstantially 10 the entire length of the reaction zone, separatelywithdrawing vapors and unvaporized oil at places remote from the placeof introduction of the heated. stream of oil from the heating zone,maintaining superatmospheric pressure in the heating 15 and reactionzone, discharging the vapors and unvaporized oil from said reaction zoneinto the lower and upper portions respectively of a reduced pressurezone where vapors flow countercurrent to non-vaporous residue, removingthe 20 residue and isolating same from the system,,subiecting the vaporsto fractionation to condense the heavier fractions thereof as refluxcondensate, returning regulated portions of said reflux condensate totheheating zone and merging same 25 with the stream of charging stock beingforced ther-ethrough, removing the vapors remaining uncondensed afterfractionation and condensing and collecting same as a distillate productof the process. 30

A. process such as claimed in claim 1, wherein said reaction zone isvertically disposed and the heated stream from the heating zone isdischarged into the upper end thereof while the vapors and unvaporizedoil are separately with- 35 awn from the lower end thereof.

3. hydrocarbon oil cracking process which comprises passing the oil in arestricted stream through a heating zone and heating the same therein tocracking temperature under pressure, 40 discharging the heated oil intothe upper portion of a vertical reaction zone maintained under crackingconditions of temperature and pressure, passing both vapors andunvaporized oil downwardly through the reaction zone and maintain- 45,

ing a low liquid level therein, removing the unvaporized oil from thebottom of the reaction zone and introducing the same into the upperportion of a flashing zone maintained under lower pressure than thereaction zone, separately removing 50 vapors from the lower portion ofthe reaction zone and introducing the same to the lower portion of theflashing zone toflow countercurrent to the unvaporized oil descendingthrough the flashing zone, and dephlegmating and condensing 55 thevapors from the flashing zone.

CARBON P. DUBBS.

